This invention relates to poly(1,3 propanediol terephthalate), referred to as 3GT or PPT, for use in making packaging materials. In particular, the present invention relates to 3GT and its copolymers that have an excellent combination of barrier, mechanical, thermal and rheological properties and are particularly suitable for use in the packaging of foodstuffs, cosmetics and pharmaceutical products.
3GT is also known as poly(1,3 propylene terephthalate), PPT or PTMT. Generally, it is made by reacting 1,3 propanediol with terephthalic acid or a lower dialkyl ester of terephthalic acid, with the subsequent polymerization of the monomer produced. Thus, as used in this specification, 3GT refers to poly(1,3 propanediol terephthalate) which may be modified with small amounts, less than 10 mole percent, of polymer repeat units derived from copolymerized monomers (or co-repeat units), so long as the crystallization behavior of the polyester is substantially the same as the xe2x80x9chomopolymerxe2x80x9d 3GT.
This invention provides a non-flavor scalping, extrusion coating resin comprising:
a. a polyester selected from poly(1,3 propanediol terephthalate) and a copolymer of 1,3 propanediol and up to about 20% by weight comonomers, and
b. a nucleation promoter selected from the group consisting of titanium dioxide, talc, amorphous silica, linear low density polyethylene, polypropylene, sodium acetate, sodium endcapped poly(ethylene terephthalate) and sodium endcapped poly(1,3 propanediol terephthalate).
The invention also provides a non-flavor scalping, extrusion coated package, comprising:
a. a backing layer, and
b. a film layer on at least one side of the backing layer, the film layer comprising:
i. a polyester selected from poly(1,3 propanediol terephthalate) and a copolymer of 1,3 propanediol and up to about 20% by weight comonomers, and
ii. a nucleation promoter selected from the group consisting of titanium dioxide, talc, amorphous silica, linear low density polyethylene, polypropylene, sodium acetate, sodium endcapped poly(ethylene terephthalate) and sodium endcapped poly(1,3 propanediol terephthalate).